Gan Vertical Power Finfets Using BN As Gate Dielectric

Over the past few decades, the semiconductor industry has undergone rapid advancements and transformative evolution, particularly in semiconductor materials. Wide bandgap (WBG) semiconductors, represented by gallium nitride (GaN) and silicon carbide (SiC), offer significant advantages over traditional silicon-based technologies. This research explores the suitability of BN as a dielectric material in GaN vertical power FinFETs, specifically targeting high-temperature applications. BN thin films are directly deposited by microwave-plasma-assisted chemical vapor deposition (CVD). The presence of BN is confirmed by X-ray photoelectron spectroscopy (XPS). GaN/BN vertical FinFETs are demonstrated for the first time with a current on-off ratio of 10. The high-resolution transmission electron microscopy (HRTEM) reveals the presence of BN on GaN non-polar sidewalls. BN metal-insulator-semiconductor (MIS) gate diode demonstrates increased breakdown voltage compared to GaN Schottky gate diode. Hydrogen plasma has been pinpointed as the main culprit behind variations in dielectric film thickness and the deterioration of crystal quality, both of which contribute to increased gate leakage current. Through the optimization of deposition conditions, the enhanced device demonstrates outstanding performance and maintains stable operation at temperatures up to 573K. This study provides a valuable foundation for future research on BN-based gate dielectrics in GaN vertical transistors.